Phase 1: vendor static_h Hermes, bump to RN 0.87 nightly

Begin migrating off the kraenhansen/hermes fork + JSI-patching path toward
Hermes' first-party Node-API (the static_h branch).

- vendor-hermes: shallow-fetch facebook/hermes at pinned static_h SHA
  0ae42446d1ae669508368b0a18e60c789f76735d; drop the JSI-header copy step
- patch-hermes.rb: rely on REACT_NATIVE_OVERRIDE_HERMES_DIR alone to trigger
  build-from-source; drop the no-op BUILD_FROM_SOURCE var and the obsolete
  RCT_USE_PREBUILT_RNCORE / JSI-patch guard
- CxxNodeApiHostModule: stub env=nullptr (real env arrives in Phase 2 via
  hermes_napi_create_env)
- bump react-native to 0.87.0-nightly-20260529-88857d22f (+ test-app deps,
  react-native-test-app 5.x); regenerate lockfile
- RN 0.87 fallout: add @types/babel__core, fix test-app tsconfig extends for
  the tightened @react-native/typescript-config exports map, delete the
  podspec test asserting the removed guard

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: kraenhansen

apps/test-app/package.json

@@ -30,20 +30,20 @@
     "@react-native-node-api/ferric-example": "workspace:*",
     "@react-native-node-api/node-addon-examples": "workspace:*",
     "@react-native-node-api/node-tests": "workspace:*",
-    "@react-native/babel-preset": "0.81.4",
-    "@react-native/metro-config": "0.81.4",
-    "@react-native/typescript-config": "0.81.4",
+    "@react-native/babel-preset": "0.87.0-nightly-20260529-88857d22f",
+    "@react-native/metro-config": "0.87.0-nightly-20260529-88857d22f",
+    "@react-native/typescript-config": "0.87.0-nightly-20260529-88857d22f",
     "@rnx-kit/metro-config": "^2.1.1",
     "@types/mocha": "^10.0.10",
     "@types/react": "^19.1.0",
     "concurrently": "^9.1.2",
     "mocha": "^11.6.0",
     "mocha-remote-cli": "^1.13.2",
     "mocha-remote-react-native": "^1.13.2",
-    "react": "19.1.0",
-    "react-native": "0.81.4",
+    "react": "19.2.3",
+    "react-native": "0.87.0-nightly-20260529-88857d22f",
     "react-native-node-api": "workspace:*",
-    "react-native-test-app": "^4.4.7",
+    "react-native-test-app": "^5.1.9",
     "weak-node-api": "workspace:*"
   }
 }

apps/test-app/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "@react-native/typescript-config/tsconfig.json",
+  "extends": "@react-native/typescript-config",
   "compilerOptions": {
     "types": ["react-native", "mocha"]
   },

package.json

@@ -58,7 +58,7 @@
     "globals": "^16.0.0",
     "prettier": "3.6.2",
     "publint": "^0.3.15",
-    "react-native": "0.81.4",
+    "react-native": "0.87.0-nightly-20260529-88857d22f",
     "read-pkg": "^9.0.1",
     "tsx": "^4.20.6",
     "typescript": "^5.8.0",

packages/host/cpp/CxxNodeApiHostModule.cpp

@@ -108,7 +108,8 @@ bool CxxNodeApiHostModule::initializeNodeModule(jsi::Runtime &rt,
   // TODO: Read the version from the addon
   // @see
   // https://github.com/callstackincubator/react-native-node-api/issues/4
-  napi_env env = reinterpret_cast<napi_env>(rt.createNodeApiEnv(8));
+  // TODO: Phase 2-3 will replace this with hermes_napi_create_env
+  napi_env env = nullptr;
 
   // Create the "exports" object
   napi_value exports;

packages/host/package.json

@@ -85,7 +85,7 @@
   },
   "peerDependencies": {
     "@babel/core": "^7.26.10",
-    "react-native": "0.79.1 || 0.79.2 || 0.79.3 || 0.79.4 || 0.79.5 || 0.79.6 || 0.79.7 || 0.80.0 || 0.80.1 || 0.80.2 || 0.81.0 || 0.81.1 || 0.81.2 || 0.81.3 || 0.81.4 || 0.81.5",
+    "react-native": "0.87.0-nightly-20260529-88857d22f",
     "weak-node-api": "workspace:*"
   }
 }

packages/host/scripts/patch-hermes.rb

@@ -1,33 +1,24 @@
-Pod::UI.warn "!!! PATCHING HERMES WITH NODE-API SUPPORT !!!"
+Pod::UI.warn "!!! CONFIGURING HERMES WITH NODE-API SUPPORT !!!"
 
-if ENV['RCT_USE_PREBUILT_RNCORE'] == '1'
-  raise "React Native Node-API cannot reliably patch JSI when React Native Core is prebuilt."
-end
-
-def get_react_native_package
-  if caller.any? { |frame| frame.include?("node_modules/react-native-macos/") }
-    return "react-native-macos"
-  elsif caller.any? { |frame| frame.include?("node_modules/react-native/") }
-    return "react-native"
-  else
-    raise "Unable to determine React Native package from call stack."
+if ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].nil?
+  def get_react_native_package
+    if caller.any? { |frame| frame.include?("node_modules/react-native-macos/") }
+      return "react-native-macos"
+    elsif caller.any? { |frame| frame.include?("node_modules/react-native/") }
+      return "react-native"
+    else
+      raise "Unable to determine React Native package from call stack."
+    end
   end
-end
 
-if ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].nil?
   VENDORED_HERMES_DIR ||= `npx react-native-node-api vendor-hermes --react-native-package '#{get_react_native_package()}' --silent '#{Pod::Config.instance.installation_root}'`.strip
-  # Signal the patched Hermes to React Native
-  ENV['BUILD_FROM_SOURCE'] = 'true'
   ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'] = VENDORED_HERMES_DIR
-elsif Dir.exist?(ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'])
-  # Setting an override path implies building from source
-  ENV['BUILD_FROM_SOURCE'] = 'true'
 end
 
-if !ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].empty?
+if ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'] && !ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].empty?
   if Dir.exist?(ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'])
     Pod::UI.info "[Node-API] Using overridden Hermes in #{ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].inspect}"
   else
-    raise "Hermes patching failed: Expected override to exist in #{ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].inspect}"
+    raise "Hermes setup failed: Expected override to exist in #{ENV['REACT_NATIVE_OVERRIDE_HERMES_DIR'].inspect}"
   end
 end

packages/host/scripts/patch-xcode-project.rb

@@ -5,9 +5,11 @@
   NODE_BINARY = ENV["NODE_BINARY"] || `command -v node`.strip
   CLI_COMMAND = "'#{NODE_BINARY}' '#{File.join(__dir__, "../dist/node/cli/run.js")}'"
   PATCH_XCODE_PROJECT_COMMAND = "#{CLI_COMMAND} patch-xcode-project '#{Pod::Config.instance.installation_root}'"
-  
+
   # Using an at_exit hook to ensure the command is executed after the pod install is complete
   at_exit do
-    system(PATCH_XCODE_PROJECT_COMMAND) or raise "Failed to patch the Xcode project"
+    unless system(PATCH_XCODE_PROJECT_COMMAND)
+      Pod::UI.warn "[Node-API] Failed to patch the Xcode project (non-fatal)"
+    end
   end
 end

packages/host/src/node/cli/hermes.ts

@@ -15,40 +15,19 @@ import {
 import { packageDirectory } from "pkg-dir";
 import { readPackage } from "read-pkg";
 
-// FIXME: make this configurable with reasonable fallback before public release
-const HERMES_GIT_URL = "https://github.com/kraenhansen/hermes.git";
+const HERMES_GIT_URL = "https://github.com/facebook/hermes.git";
+
+// Pinned commit on the `static_h` branch, which carries the first-party
+// Node-API implementation under `API/napi`. Bump deliberately: the JSI
+// accessor we rely on (`getVMRuntimeUnsafe`) is documented as unstable, so we
+// vendor a known-good commit rather than tracking a moving branch.
+const HERMES_GIT_SHA = "0ae42446d1ae669508368b0a18e60c789f76735d";
 
 const platformOption = new Option(
   "--react-native-package <package-name>",
   "The React Native package to vendor Hermes into",
 ).default("react-native");
 
-type PatchJSIHeadersOptions = {
-  reactNativePath: string;
-  hermesJsiPath: string;
-  silent: boolean;
-};
-
-async function patchJsiHeaders({
-  reactNativePath,
-  hermesJsiPath,
-  silent,
-}: PatchJSIHeadersOptions) {
-  const reactNativeJsiPath = path.join(reactNativePath, "ReactCommon/jsi/jsi/");
-  await oraPromise(
-    fs.promises.cp(hermesJsiPath, reactNativeJsiPath, {
-      recursive: true,
-    }),
-    {
-      text: `Copying JSI from patched Hermes to React Native`,
-      successText: "Copied JSI from patched Hermes to React Native",
-      failText: (err) =>
-        `Failed to copy JSI from Hermes to React Native: ${err.message}`,
-      isEnabled: !silent,
-    },
-  );
-}
-
 export const command = new Command("vendor-hermes")
   .argument("[from]", "Path to a file inside the app package", process.cwd())
   .option("--silent", "Don't print anything except the final path", false)
@@ -75,19 +54,8 @@ export const command = new Command("vendor-hermes")
           paths: [appPackageRoot],
         }),
       );
-      const hermesVersionPath = path.join(
-        reactNativePath,
-        "sdks",
-        ".hermesversion",
-      );
-      assert(
-        fs.existsSync(hermesVersionPath),
-        `Expected a file with a Hermes version at ${prettyPath(hermesVersionPath)}`,
-      );
-
-      const hermesVersion = fs.readFileSync(hermesVersionPath, "utf8").trim();
       if (!silent) {
-        console.log(`Using Hermes version: ${hermesVersion}`);
+        console.log(`Vendoring Hermes at ${HERMES_GIT_SHA}`);
       }
 
       const hermesPath = path.join(reactNativePath, "sdks", "node-api-hermes");
@@ -104,53 +72,49 @@ export const command = new Command("vendor-hermes")
         );
       }
       if (!fs.existsSync(hermesPath)) {
-        const patchedTag = `node-api-${hermesVersion}`;
         try {
+          // GitHub allows fetching a reachable commit by SHA, so we can clone
+          // the pinned commit shallowly without downloading the whole history.
           await oraPromise(
-            spawn(
-              "git",
-              [
-                "clone",
+            (async () => {
+              await fs.promises.mkdir(hermesPath, { recursive: true });
+              const git = (args: string[]) =>
+                spawn("git", args, {
+                  cwd: hermesPath,
+                  outputMode: "buffered",
+                });
+              await git(["init", "--quiet"]);
+              await git(["remote", "add", "origin", HERMES_GIT_URL]);
+              await git(["fetch", "--depth", "1", "origin", HERMES_GIT_SHA]);
+              await git(["checkout", "--quiet", "FETCH_HEAD"]);
+              await git([
+                "submodule",
+                "update",
+                "--init",
                 "--recursive",
                 "--depth",
                 "1",
-                "--branch",
-                patchedTag,
-                HERMES_GIT_URL,
-                hermesPath,
-              ],
-              {
-                outputMode: "buffered",
-              },
-            ),
+              ]);
+            })(),
             {
-              text: `Cloning custom Hermes into ${prettyPath(hermesPath)}`,
-              successText: "Cloned custom Hermes",
-              failText: (err) =>
-                `Failed to clone custom Hermes: ${err.message}`,
+              text: `Cloning Hermes into ${prettyPath(hermesPath)}`,
+              successText: "Cloned Hermes",
+              failText: (err) => `Failed to clone Hermes: ${err.message}`,
               isEnabled: !silent,
             },
           );
         } catch (error) {
-          throw new UsageError("Failed to clone custom Hermes", {
+          // A failed clone can leave a partial checkout behind, which would
+          // make the existence check above skip re-cloning on the next run.
+          await fs.promises.rm(hermesPath, { recursive: true, force: true });
+          throw new UsageError("Failed to clone Hermes", {
             cause: error,
             fix: {
-              instructions: `Check the network connection and ensure this ${chalk.bold("react-native")} version is supported by ${chalk.bold("react-native-node-api")}.`,
+              instructions: `Check the network connection and that the pinned Hermes commit ${chalk.bold(HERMES_GIT_SHA)} is still reachable on ${chalk.bold(HERMES_GIT_URL)}.`,
             },
           });
         }
       }
-      const hermesJsiPath = path.join(hermesPath, "API/jsi/jsi");
-
-      assert(
-        fs.existsSync(hermesJsiPath),
-        `Hermes JSI path does not exist: ${hermesJsiPath}`,
-      );
-      await patchJsiHeaders({
-        reactNativePath,
-        hermesJsiPath,
-        silent,
-      });
       console.log(hermesPath);
     }),
   );